Push rod



PUSH ROD Filed June 14. 1927 1 j 4 4 H 4 iii? 7 93 21 12 v 36 fl/vo sJ tzj g7 INVENTOR (7 1% 57 BY W 1 ATTORNEY.

Patented Feb. 21, 1928.

UNITED STATES PATENT OFFICE.

FUSE BOD.

Application filed June 14,

The present invention relates to hydraulically cushioned push rods, such as those employed for lifting the valves of internal combustion engines, and of the type such as that described in my Patent No. 1,515,344,

Nov. 11, 1924. r

An object of the present invention is to provide a push rod in which alLthe working parts are thoroughly inclosed for their protection, and which push rod is ca able of; increasing in eflective length rapid y to take up lost motion; decreasing slowly in efl'ective len h to compensate for expansion; and further capable of resisting sudden appre- 16 ciable decrease in length.

Another object of my invention is to rovide a hydraulically cushioned push ro in which the fluid is housed against escape, oxidation and contamination with dust or other foreign substance.

Another object of my invention is to provide a device of the class described in the form of a complete self-contained assembly, which may be readily applied to many various makes of engines, or which by slight change of design is adaptable to the majority of en nes.

Another 0 ject of my invention is to provide an improved check valve for such devices.

Another object of the invention is the provision of improved construction to facilitate manufacture, assembly, replacement, repair, and long life.

Other objects and advantages. of my invention will appear hereinafter.

I have illustrated by the accompanying drawings one practical embodiment of my invention. which by slight changes of design is adaptable to practically all types of automobile and other puppet valve engines, and which device is suitable for many other purposes where a self-adjusting push rod or the like is required.

In the said drawings:

Figure 1 is a view in elevation of the said embodiment.

Figure 2 is a view in vertical section thereof on a larger scale.

Figure 3 is a view in cross section on line 33 of Fig. 2.

' Figure 4.- is a view in section on line 4-4 of Fig. 2.

In carrying out my invention in the present embodiment I employ an elongated metal cylinder 5 of comparatively small diameter 1927. Serial No. 188,746.

and provided at the upper end with a screwvided with a central bore 11, extending thru.

same from end to end. Said plun er divides the hollow interior of the cylin er into a lower or hydraulic chamber 12, and an upper or overflow chamber 14. The bore 11 is counterbored as at 15. A push rod extension 20, of smaller diameter, is attached to said piston by being securely pressed into the counterbore 15. The extension has a short bottom cavity 16, which forms a continuation of the bore 11. In this cavity overflow apertures 17 are provided leading from cavity 16 out thru the sides of the extension 20 into the overflow space 14:. At the lower end of the bore 11, of the plunger, there is provided an annular valve seat 19.

A tapered valve 21 is arranged to seat upwardly on said seat and is loosely contained within said plunger. This valve has a stem which is of polygonal cross section, as at 22, and of round cross section as at 23. The polygonal part of the stem is fitted fairly close in the bore of the plunger to guide the valve while permitting of fluid by passing said stem. At the upper end of the valve stem, as at 24, a spring 25 is attached. This spring is housed in the bore 11 of the plunger and terminates in a hooked end 26, which passes out thru one of apertures 17. In assembling the valve in the open end of the plunger the springs upper end is forced up thru the bore 11 and out thru aperture 17. Then the end of the spring is drawn outwardly until the spring is properly tensioned. so that it holds the valve yieldably on its seat.

At the part of the extension 20, where it first enters the top closure, I provide an annular groove 27 A spring ring 28 is moved slidably over the extension until it snaps into the groove. This ring then becomes a substantially fixed part of the extension 20 and provides an annular enlargement therefor. The plunger and its extension is then inserted in the bore of the cylinder top closure of the cylinder is fitted over the extension 20 and screwed into place. The ring 28 then limits the outward movement and the .of the plunger in its cylinder and is so located that the hydraulic chamber 12 is shallow even when the plunger is in outermost position. I

Above the closure wall and restin on the top thereof there is provided an annu ar compressible gasket or washer 30 which is a close fit around the extension 20. Above this gasket a metal washer 31 is fitted. Upwardly of the extension at an appreciable distance above the cylinders closure, I provide another ring 32 which fits in a groove 33 similar to the manner in which the ring 28 fits in the groove 27. -This ring limits the upward movement of a collar 34 which is movably fitted around the extension 20.

Between the collar 34: and thewasher 31 a strong compression spring 35 is located. This spring acting between the collar and the washer acts to hold the plunger in uppermost position at all times. The tension of this sprin should be limited according to the conditions under which the rod is to be operated. The spring also urges the metal washer down upon the resilient washer sufficiently to cause the resilient washer to expand laterally in both directions and to closely engage the surface of the extension 20 to provide an oil tight gland where the extenslon passes out the to closure-of the cylinder. The cylinder is c osed at the bottom, as at 36, and is provided with a lug 37 or the like, whereby it may be fitted into a valve tappet (not shown).

In describing the operation of this device it will be assumed, as is the case in internal combustion engines, that a thrust from the bottom of the device upwardl is to be conveyed by the rod to an over ead valve or the like (not shown). When the usual sudden thrust occurs, the fluid in the hydraulic chamber may resist it to such extent that fluid under pressure will slip by the plunger into the overflow space with the result that the plunger will move down very slightly in the cylinder, thus shortening the total effective length of, the push rod. The valve in the plunger of course prevents any fluid from reaching the overflow space, except by slipping by the plunger, and the plunger is a suitably close fit'to suitably resist such flow. When the thrust on the rod is relieved, the spring acts to lift the plunger as high as permitted, and the hydraulic chamber at the lower end of the cylinder below the piston is increased. This creates a suction therein which will open the check valve downwardly and draw oil from the overflow space back into the hydraulic chamber. The rod is now extended to normal-length and is again ready to transmit a thrust while being capable of resisting sudden appreci able decrease in length. The advantages of such a push rod are well known and are clearly set forth in my said patent. Should the rods be idle, but subject to increased temperatureso that its extension 20 expands, the effective length of the rod will not increase because it is self adjusting.

It will be apparent now that I have provided a rod of the class described and for the purpose set forth, and while I have shown and described a Specific construction and arrangement of parts and have indicated certain uses for the rod, I do not limit myself to any specific construction or arrangement of parts, or to any specific use or uses, andI may employ other construc tions or may variously depart from the construction Withoutenlarging the scope of my invention as set forth in the appended claims.

I claim 1. In a device of the class described, a cylinder closed at the lower end, a closure at the upper end of said cylinder providing a central aperture, a piston fitting closely in said cylinder and providing an overflow space in said cylinder above the iston and further providing a hydraulic c amber in said cylinder below said piston; said piston being provided with a through bore-from end to end thereof and providing a valve seat adjacent the hydraulic chamber, a push rod fitted into said bore; the end of said push rod where it is inserted into sald bore being hollow and opening into said overflow space; said push rod extending out through the aperture in said closure.

2. The device as in claim 1, and further including a collar on said push rod outward- 1y of said cylinder, a compressible washer resting on said closure, another washer above the compressible washer, and a s rin compressed between said shoulder an sai other washer.

3. The device as in claim 1, and further incuding a coil spring in the bore of said piston; said spring connected at one end to 1 said valve; the other end of said spring be-v ing attached to said piston by passing outwardly through the bore of said piston where it opens to said overflow s ace.

4. The device as in claim 1, and further includin a collar on said push rod outwardly of said cylinder, a compressible washer resting on said closure, another washer above the compressible washer, a spring compressed between said shoulder and said other washer, a coil spring in the bore of said piston; said spring connected at one end to said valve; the other end of said spring being attached to said piston by passing outwardly through the bore of said piston where it opens to said overflow space.

5. In a device of the class described, a cylinder having top and bottom closure walls respectively, a piston Working in said cylinder and providing an overflow space between the piston and the top closure wall and further providing a hydraulic chamber between the piston and the bottom closure wall, a push rod attached to said piston and passing outwardly through the top closure wall; said piston providln a fluid course extending centrally thereof from said hydraulic chamber to the overflow space, a downwardly opening non-return valve in said fluid course, and a spring urging said piston upwardly in said cylinder.

6. In a device of the class described, a cylinder closed at the lower end, a closure at the upper end of said cylinder providing a central a erture, a'piston fitting closely in said cylin, er and providing an overflow space in said cylinder above the iston and further providing a hydraulic c amber in said cylinder below said iston; said piston being provided with a t rough bore from end to end thereof and roviding a valve seat adjacent the h draulic chamber, a push rod fitted into said re; the end of said push rod where it is inserted into said bore being hollow and opening into said overflow space; said push rod extending out through the aperture insaid closure; said push rod formed with a circumferential groove below said closure, a spring ring fitted in said groove to abut said closure, a collar on said rod above said closure, and a compression spring between said collar and said closure.

7. The device as in claim 1, and further including said push rod formed with a. circumferential groove below said closure, a s ring ring fitted in said groove to abut said c osure, a collar on said rod above said closure, and a compression spring between said collar and said closure; said collar loose- 1y encompassing said push rod; said rod formed with a second circumferential groove adjacent said collar, and a spring fitted in said second circumferential groove; said com ression spring urging said collar upwar 1y against said ring.

AMOS B. JOY. 

